TCT: Endeavor Edges Out Taxus at Three Years

Action Points

Explain to interested patients that this is report is based on a post-hoc analysis of long-term data from a study that did not meet its primary endpoint, which was target vessel failure at nine months.

Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

SAN FRANCISCO -- Time appears to favor a zotarolimus-eluting stent (Endeavor) over a paclitaxel-eluting stent (Taxus), according to results reported here.

The three-year cardiac death rate with the zotarolimus-eluting stent was 3.7% versus 7.1% with the paclitaxel-eluting comparator (P=0.005). The MI rate was 1.8% versus 4.2% (P =0.009), and the stent thrombosis rate from 360 to 1,080 days was 0.1% versus 1.5% (P=0.006), in findings reported today at the Transcatheter Cardiovascular Therapeutics meeting here.

The findings extend the two-year ENDEAVOR IV results, but those results were eclipsed by findings from a trial that compared the zotarolimus-eluting stent with the sirolimus-eluting CYPHER stent.

In that match-up -- known as the SORT-OUT III trial -- Cypher was the clear winner as the hazard ratio for MI at nine months was 3.476 for patients treated with Endeavor stents versus the Cypher-treated patients (95% CI 1.12 to 10.5, P=0.03).

The 36-month ENDEAVOR IV results were reported by Martin B. Leon, MD, chairman of the Cardiovascular Research Foundation -- sponsors of TCT -- and David E. Kandzari, MD, director of interventional cardiology research at Scripps Clinic in La Jolla.

The ENDEAVOR IV trial randomized 774 patients with a single (2.5 mm to 3.5 mm) de novo lesion to Endeavor and an equal number to the Taxus stent. The primary endpoint was target vessel failure (TVF) at nine months, with in-segment percent diameter stenosis at eight months, and target lesion revascularization (TLR) and target vessel revascularization (TVR), both at nine months.

All patients were on dual antiplatelet therapy with clopidogrel (Plavix) and aspirin for at least six months.

ENDEAVOR IV was designed as a non-inferiority trial and at the nine-month point TVF was not inferior to the comparator. But here again the numbers improved with time so that at 36 months there was a significant reduction in TVF, 12.3% versus 15.9%, which worked out to a 24% reduction in relative risk (0.76, 95% CI 0.58 to 1.00, P=0.049).

Using the three-year data, treating 27 patients with the Endeavor stent would prevent one cardiac death compared with cardiac mortality in Taxus-treated patients.

Of note, when the cardiac death and MI rates are considered together, the rate of these events increased more sharply among the Taxus-treated patients, climbing form 3.1% at one year to 7.1% at three years, versus an increase from 2.1% at one year to 3.6% at three years.

Using the Academic Research Consortium (ARC) definitions for probable and definite very late stent thrombosis -- meaning an event that occurs more than 12 months after stenting -- treating 71 patients with an Endeavor stent would prevent a single stent thrombosis compared with Taxus-treated patients.

There was one very late stent thrombosis in the Endeavor arm versus 11 in the control group.

Leon and Kandzari said an analysis of patients with diabetes -- 224 in the Endeavor group and 218 in Taxus group -- found no significant differences in TLR, TVR, or TVF.

But there were fewer cardiac deaths -- six in the Endeavor group versus 16 in the Taxus group (P=0.029).

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